16 DEPARTMENT BULLETIN 1216, U. S. DEPT. OF AGRICULTURE 
SAMPLING OF MISCELLANEOUS MATERIALS 
23. Samples of slag sand, screenings, mine tailings, and all other materials 
used as a substitute for sand and gravel or broken stone shall be inspected in 
the same manner and samples taken in the same way as the materials for 
which they are substituted. 
SAMPLING OF STONE BLOCK 
24. Samples shall be taken either at the quarry or from cars or boats as di- 
rected by the engineer. They shall be representative of the block which it is 
proposed to use and no sample shall include blocks that would be rejected by 
visual inspection. 
25. The sample shall consist of at least six blocks and the bedding plane 
shall be marked on at least two of these. 
GENERAL DIRECTIONS FOR SHIPPING AND MARKING SAMPLES 
26. Samples of ledge stone, crushed stone, and slag shall be shipped in a 
secure box or bag. 
27. Samples of stone block shall be securely crated. 
28. Samples of run-of-bank gravel, sand screenings, and other fine material 
shall be shipped in a tight box or closely woven bag so there shall be no loss of 
the finer particles. 
29. Each sample or separate container shall be accompanied by a card or 
regular form, preferably in the container, giving the following information : 
By whom taken, official title or rank of the sampler ; by whom submitted ; 
source of supply; proposed use for the material; and in case of commercial 
supplies, daily production ; geographic location, shipping facilities (name of 
railroad, canal or river, or other common carrier) ; and price of the material. 
3. METHOD OF TEST FOR ABRASION OF BROKEN STONE 
AND BROKEN SLAG 
(Based on A. S. T. M. standard method <)). serial designation D 2-i;ti i 
1. The machine shall consist of one or more hollow iron cylinders, closed at 
one end and furnished with a tightly fitting iron cover at the other: the cylin- 
ders to be 20 centimeters in diameter and 34 centimeters in depth inside. These 
cylinders shall be mounted on a shaft at an angle of 30° with the axis of 
rotation of the shaft. 
2. The rock to be tested shall be broken in the laboratory from pieces at 
least Zy<2 inches in size to as nearly uniform size and shape as possible, and 
as near to 50 pieces as possible shall constitute a test sample. No pieces with 
edges or faces that have been rounded by wear shall be included. The total 
weight of rock in a test shall be within 10 grams of 5 kilograms. All test pieces 
shall be washed and- thoroughly dried before weighing. Ten thousand revolu- 
tions, at a rate of between 30 and 33 per minute, shall constitute a test. Only 
the percentage of material worn off which will pass through an American 
Society for Testing Materials standard No. 12 sieve shall, be considered in 
determining the amount of wear. This shall be expressed as a percentage 
of the 5 kilograms used in the test. 
Note. — In the case of broken stone, samples should, wherever possible, be selected 
from the quarry face. 
3. When the material has a specific gravity below 2.20 the quantity used for 
the test shall be adjusted on a weight basis, retaining the specified number 
of pieces. For such materials a weight of 4,00* ) grams of the broken stone 
or broken slag shall be used. 
4. The results shall be reported as percentage of wear. 
5. The operator is cautioned that drying some varieties of stone at high tem- 
peratures has a deleterious effect upon the abrasion loss, and therefore care 
